In addition to washing machines which wash clothes, there are many kinds of clothes treating apparatuses that are currently used. For an example, developed recently are drum type dryers for drying washed clothes, housing type dryers for drying the clothes while the clothes are hung up, and refreshers for refreshing clothes by supplying hot air to the clothes.
In these refresher or dryer-type clothes treating apparatuses the air is heated with a heater and supplied to the clothes. Various types of heaters are available, such as gas heaters, which burn gas to heat air, and electric heaters which heat the air with electric resistance. Currently, electric heaters are used mostly, as they are convenient to install, and have simple structure.
There are certain drawbacks to using electrical heaters in clothes drying apparatuses. If the air is heated with the electric heater, air having a dangerously high temperature may be transferred directly to the clothes, which may damage the clothes or worse, cause a fire in the clothes treating apparatus. Moreover, electric heaters consume large quantities of electricity when used to heat the air to a desired temperature, therefore, much maintenance expense is required.